Tilt sensor and method of providing the same

ABSTRACT

A tilt sensor contains a first electrically conductive element, a second electrically conductive element, an electrically insulative element, and a plurality of electrically conductive weights. The electrically insulative element is connected to the first electrically conductive element and the second electrically conductive element. In addition, the plurality of electrically conductive weights are located within a cavity of the tilt sensor, wherein the cavity is defined by at least one surface of the first electrically conductive element, at least one surface of the electrically insulative element, and at least one surface of the second electrically conductive element.

FIELD OF THE INVENTION

The present invention is generally related to sensors, and moreparticularly is related to a tilt sensor.

BACKGROUND OF THE INVENTION

Many different electrical tilt switches are presently available andknown to those having ordinary skill in the art. Typically, tiltswitches are used to switch electrical circuits ON and OFF depending onan angle of inclination of the tilt switch. These types of tilt switchestypically contain a free moving conductive element located within theswitch, where the conductive element contacts two terminals when theconductive element is moved into a specific position, thereby completinga conductive path. An example of this type of tilt switch is a mercuryswitch. Unfortunately, it has been proven that use of Mercury may leadto environmental concerns, thereby leading to regulation on Mercury useand increased cost of Mercury containing products, including switches.

To replace Mercury switches, newer switches use a conductive elementcapable of moving freely within a confined area. A popularly usedconductive element is a single metallic ball. Tilt switches having asingle metallic ball are capable of turning ON and OFF in accordancewith a tilt angle of the tilt switch. Certain tilt switches also containa ridge, a bump, or a recess, that prevents movement of the singlemetallic ball from a closed position (ON) to an open position (OFF)unless the tilt angle of the tilt switch is in excess of a predeterminedangle.

An example of a tilt switch requiring exceeding of a tilt angle of thetilt switch is provided by U.S. Pat. No. 5,136,157, issued to Blair onAug. 4, 1992 (hereafter, the '157 patent). The '157 patent discloses atilt switch having a metallic ball and two conductive end piecesseparated by a non-conductive element. The two conductive end pieceseach have two support edges. A first support edge of the firstconductive end piece and a first support edge of the second conductiveend piece support the metallic ball there-between, thereby maintainingelectrical communication between the first conductive end piece and thesecond conductive end piece. Maintaining electrical communicationbetween the first conductive end piece and the second conductive endpiece keeps the tilt switch in a closed state (ON). To change the tiltswitch into an open state (OFF), the metallic ball is required to bemoved so that the metallic ball is not connected to both the firstconductive end piece and the second conductive end piece. Therefore,changing the tilt switch to an open state (OFF) requires tilting of the'157 patent tilt switch past a predefined tilt angle, thereby removingthe metallic ball from location between the first and second conductiveend piece. Unfortunately, tilt switches are generally constructed with aform factor that is difficult to attach to printed circuit boards usingautomated manufacturing equipment, and are costly to produce because ofneed to assemble numerous separate parts to form the switch.

Thus, a heretofore unaddressed need exists in the industry to addressthe aforementioned deficiencies and inadequacies.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a tilt sensor and a methodof construction thereof. Briefly described, in architecture, oneembodiment of the system, among others, can be implemented as follows.The tilt sensor contains a first electrically conductive element, asecond electrically conductive element, an electrically insulativeelement, and a plurality of electrically conductive weights. Theelectrically insulative element is connected to the first electricallyconductive element and the second electrically conductive element. Inaddition, the plurality of conductive weights are located within acavity of the tilt sensor, wherein the cavity is defined by at least onesurface of the first electrically conductive element, at least onesurface of the electrically insulative element, and at least one surfaceof the second electrically conductive element.

The present invention can also be viewed as providing methods forassembling a tilt sensor having a first electrically conductive element,a second electrically conductive element, an electrically insulativeelement, and a plurality of electrically conductive weights. In thisregard, one embodiment of such a method, among others, can broadly besummarized by the following steps: fitting a distal portion of the firstelectrically conductive element within a hollow center of theelectrically insulative member; positioning the plurality ofelectrically conductive weights within the hollow center of theelectrically insulative member; and fitting a distal portion of thesecond electrically conductive element within the hollow center of theelectrically insulative member.

Other systems, methods, features, and advantages of the presentinvention will be or will become apparent to one with skill in the artupon examination of the following drawings and detailed description. Itis intended that all such additional systems, methods, features, andadvantages be included within this description, be within the scope ofthe present invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the invention can be better understood with reference tothe following drawings. The components in the drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the present invention. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is an exploded perspective side view of the present tilt sensor,in accordance with a first exemplary embodiment of the invention.

FIG. 2 is a cross-sectional side view of the first end cap of FIG. 1.

FIG. 3A is a cross-sectional side view of the central member of FIG. 1,in accordance with the first exemplary embodiment of the invention.

FIG. 3B is a cross-sectional side view of the central member of FIG. 1,in accordance with an alternative embodiment of the invention.

FIG. 4 is a cross-sectional side view of the second end cap of FIG. 1.

FIG. 5 is a flowchart illustrating a method of assembling the tiltsensor of FIG. 1.

FIG. 6A and FIG. 6B are cross-sectional side views of the tilt sensor ofFIG. 1 in a closed state (ON), in accordance with the first exemplaryembodiment of the invention.

FIG. 6C is a cross-sectional side view of the tilt sensor having thecentral member of FIG. 3B.

FIG. 6D is a cross-sectional side view of the tilt sensor of FIG. 1having a single conductive sphere, in accordance with an alternativeembodiment of the invention.

FIG. 6E is a cross-sectional side view of the tilt sensor of FIG. 1having a gap between the first end cap and the second end cap.

FIGS. 7A, 7B, 7C, and 7D are cross-sectional side views of the tiltsensor of FIG. 1 in an open state (OFF), in accordance with the firstexemplary embodiment of the invention.

FIG. 8 is a cross-sectional side view of a tilt sensor, in accordancewith a third exemplary embodiment of the invention.

FIG. 9 is a cross-sectional side view of a tilt sensor, in accordancewith a fourth exemplary embodiment of the invention.

FIG. 10 is a cross-sectional side view of a tilt sensor, in accordancewith a fifth exemplary embodiment of the invention.

FIG. 11A and FIG. 11B are cross-sectional side views of a tilt sensor,in accordance with a sixth exemplary embodiment of the invention.

DETAILED DESCRIPTION

The following describes a tilt sensor. The tilt sensor contains aminimal number of cooperating parts to ensure ease of assembly and use.FIG. 1 is an exploded perspective side view of the present tilt sensor100, in accordance with a first exemplary embodiment of the invention.

Referring to FIG. 1, the tilt sensor 100 contains a first end cap 110, acentral member 140, a second end cap 160, and multiple weights embodiedas a pair of conductive balls 190 that are spherical in shape(hereafter, conductive spheres). Specifically, the first end cap 110 isconductive and may be constructed from a composite of high conductivityand/or low reactivity metals, a conductive plastic, or any otherconductive material.

FIG. 2 is a cross-sectional side view of the first end cap 110, whichmay be referred to for a better understanding of the location ofportions of the first end cap 110. The first end cap 110 has a proximateportion 112 and a distal portion 122. The proximate portion 112 of thefirst end cap 110 is circular, having a diameter D 1, and having a flatend surface 114. A top surface 116 of the proximate portion 112 runsperpendicular to the flat end surface 114. A width of the top surface116 is the same width as a width of the entire proximate portion 112 ofthe first end cap 110. The proximate portion 112 also contains aninternal surface 118 located on a side of the proximate portion 112 thatis opposite to the flat end surface 114, where the top surface 116 runsperpendicular to the internal surface 118. Therefore, the proximateportion 112 is in the shape of a disk. This disk shaped portion of thefirst end cap 110 is also referred to herein as a flange of the firstend cap 110.

It should be noted that while FIG. 2 illustrates the proximate portion112 of the first end cap 110 having a flat end surface 114, and FIG. 4illustrates the proximate portion 162 (FIG. 4) of the second end cap 160as having a flat surface 164 (FIG. 4), one having ordinary skill in theart would appreciate that the proximate portions 112, 162 (FIG. 4) donot require presence of a flat end surface. Instead, the flat endsurfaces 114, 164 may be convex or concave. In addition, instead ofbeing circular, the first end cap 110 and the second end cap 160 may besquare-like in shape, or they may be a different shape. Use of circularend caps 110, 160 is merely provided for exemplary purposes. The mainfunction of the end caps 110, 160 is to provide a conductive connectionthat allows an electrical charge introduced to the first end cap 110 totraverse the conductive spheres 190 and be received by the second endcap 160, therefore, many different shapes and sizes of end caps 110, 160may be used as long as the conductive path is maintained.

The relationship between the top portion 116, the flat end surface 114,and the internal surface 118 described herein is provided for exemplarypurposes. Alternatively, the flat end surface 114 and the internalsurface 118 may have rounded or otherwise contoured ends resulting inthe top surface 116 of the proximate portion 112 being a natural roundedprogression of the end surface 114 and the internal surface 118.

The distal portion 122 of the first end cap 110 is tube-like in shape,having a diameter D2 that is smaller than the diameter D1 of theproximate portion 112. The distal portion 122 of the first end cap 10contains a top surface 124 and a bottom surface 126. The bottom surface126 of the distal portion 122 defines an exterior portion of acylindrical gap 128 located central to the distal portion 122 of thefirst end cap 110. A diameter D3 of the cylindrical gap 128 is smallerthan the diameter D2 of the distal portion 122.

Progression from the proximate portion 112 of the first end cap 110 tothe distal portion 122 of the first end cap 110 is defined by a stepwhere a top portion of the step is defined by the top surface 116 of theproximate portion 112, a middle portion of the step is defined by theinternal surface 118 of the proximate portion 112, and a bottom portionof the step is defined by the top surface 124 of the distal portion 122.

The distal portion 122 of the first end cap 110 also contains an outersurface 130 that joins the top surface 124 and the bottom surface 126.It should be noted that while FIG. 2 shows the cross-section of theouter surface 130 as being squared to the top surface 124 and the bottomsurface 126, the outer surface 130 may instead be rounded or of adifferent shape.

As is better shown by FIG. 2, the distal portion 122 of the first endcap 110 is an extension of the proximate portion 112 of the first endcap 110. In addition, the top surface 124, the outer surface 130, andthe bottom surface 126 of the distal portion 122 form a cylindrical lipof the first end cap 110. As is also shown by FIG. 2, the distal portion122 of the first end cap 110 also contains an inner surface 132, thediameter of which is equal to or smaller than the diameter D3 of thecylindrical gap 128. While FIG. 2 illustrates the inner surface 132 asrunning parallel to the flat end surface 114, as is noted hereafter, theinner surface 132 may instead be concave, conical, or hemispherical. Alength LI of the cylindrical gap 128 extends from the inner surface 132of the first end cap 110 to the outer surface 130 of the first end cap110.

It should be noted that the length L1 of the cylindrical gap 128 maydiffer, as long as a central cavity (200) of the tilt sensor 100 is longenough to fit the conductive spheres 190 therein without having theconductive spheres 190 touching both the first end cap 110 and thesecond end cap 160 at the same time.

Referring to FIG. 1 and FIG. 3A, the central member 140 of the sensor100 is tube-like in shape, having a top surface 142, a proximate surface144, a bottom surface 146, and a distal surface 148. FIG. 3A is across-sectional side view of the central member 140 and may also bereferred to for a better understanding of the location of portions ofthe central member 140. It should be noted that the central member 140need not be tube-like in shape. Alternatively, the central member 140may have a different shape, such as, but not limited to, that of arectangle.

The bottom surface 146 of the central member 140 defines a hollow center150 having a diameter D4 that is just slightly larger than the diameterD2 (FIG. 2), thereby allowing the distal portion 122 of the first endcap 110 to fit within the hollow center 150 of the central member 140(FIG. 3A). In addition, the top surface 142 of the central member 140defines the outer surface of the central member 140 where the centralmember 140 has a diameter D5. It should be noted that the diameter D1(i. e., the diameter of the proximate portion 112 of the first end cap110) is preferably slightly larger than diameter D5 (i.e., the diameterof the central member 140). Of course, different dimensions of thecentral member 140 and end caps 110, 160 may also be provided. Inaddition, when the tilt sensor 100 is assembled, the proximate surface144 of the central member 140 rests against the internal surface 118 ofthe first end cap 110.

Unlike the first end cap 110 and the second end cap 160, the centralmember 140 is not electrically conductive. As an example, the centralmember 140 may be made of plastic, glass, or any other nonconductivematerial. In an alternative embodiment of the invention, the centralmember 140 may also be constructed of a material having a high meltingpoint that is above that used by commonly used soldering materials. Asis further explained in detail below, having the central member 140non-conductive ensures that the electrical conductivity provided by thesensor 100 is provided through use of the conductive spheres 190.Specifically, location of the central member 140 between the first endcap 110 and the second end cap 160 provides a non-conductive gap betweenthe first end cap 110 and the second end cap 160.

A length L2 of the hollow center 150 extends from the proximate surface144 of the central member 140 to the distal surface 148 of the centralmember 140. It should be noted that the length L1 of the cylindrical gap128 is smaller than the length L2 of the hollow center 150.

FIG. 3B is a cross-sectional side view of the central member of FIG. 3A,in accordance with an alternative embodiment of the invention, where thecentral member 600 contains a top surface 610 and an outer lip 620. Atop portion of the outer lip 620 is the top surface 610. The outer lip620 also contains an outer lip end surface 622 and an outer lip bottomsurface 624, where the outer lip bottom surface 624 is perpendicular tothe outer lip end surface 622. Of course, the outer lip bottom surface624 is not required to be perpendicular to the outer lip end surface622. Similar to the central member of FIG. 3A, the central member 600 ofFIG. 3B contains a proximate surface 144, a bottom surface 146, a distalsurface 148, and a hollow center 150.

The top surface 610 of the central member 600 has a length L4, while alength L2 of the hollow center 150 extends from the proximate surface144 of the central member 600 to the distal surface 148 of the centralmember 600. The outer lip end surface 622 extends a distance ½ (L4−L2)from either the proximate surface 144 or from the distal surface 148 ofthe central member 600. The distance ½ (L4−L2) is the same or largerthan the width of the top surface 116 of the proximate portion 112 ofthe first end cap 110, thereby having the first end cap 110 and thesecond end cap 160 within the central member 600.

As in the central member 140 of FIG. 3A, the bottom surface 146 of thecentral member 600 of FIG. 3B defines the hollow center 150 having thediameter D4 that is just slightly larger than the diameter D2 (FIG. 2),thereby allowing the distal portion 122 of the first end cap 11O to fitwithin the hollow center 150 of the central member 600. In addition, thedistance between the bottom lip surface 624 of the central member 600defines a diameter D8. It should be noted that the diameter D1 (i.e.,the diameter of the proximate portion 112 of the first end cap 110) ispreferably slightly smaller than diameter D8. In addition, a diameter D6(i. e., a diameter of the proximate portion 162 of the second end cap160) is preferably slightly smaller than diameter D8. Of course,different dimensions of the central member 600 and end caps 110, 160 mayalso be provided. In addition, when the tilt sensor 100 is assembled,the proximate surface 144 of the central member 600 rests against theinternal surface 118 of the first end cap 110, and the bottom lipsurface 624 of the central member 600 rests against the top surface 116of the proximate portion 112. Further, when the tilt sensor 100 isassembled, the distal surface 148 of the central member 600 restsagainst an internal surface 168 of the second end cap 160, and thebottom lip surface 624 of the central member 600 rests against the topsurface 166 of the proximate portion 162.

Referring to FIG. 1 and FIG. 4, the second end cap 160 is conductive,having a proximate portion 162 and a distal portion 172. Specifically,the second end cap 160 may be constructed from a composite of highconductivity and/or low reactivity metals, a conductive plastic, or anyother conductive material.

FIG. 4 is a cross-sectional side view of the second end cap 160, whichmay be referred to for a better understanding of the location ofportions of the second end cap 160. The proximate portion 162 of thesecond end cap 160 is circular, having a diameter D6, and having a flatend surface 164. A top surface 166 of the proximate portion 162 runsperpendicular to the flat end surface 164. A width of the top surface166 is the same width as a width of the entire proximate portion 162 ofthe second end cap 160. The proximate portion 162 also contains aninternal surface 168 located on a side of the proximate portion 162 thatis opposite to the flat end surface 164, where the top surface 166 runsperpendicular to the internal surface 168. Therefore, the proximateportion 162 is in the shape of a disk. This disk shaped portion of thesecond end cap 160 is also referred to herein as a flange of the secondend cap 160.

The relationship between the top portion 166, the flat end surface 164,and the internal surface 168 described herein is provided for exemplarypurposes. Alternatively, the flat end surface 164 and the internalsurface 168 may have rounded or otherwise contoured ends resulting inthe top surface 166 of the proximate portion 162 being a natural roundedprogression of the end surface 164 and the internal surface 168.

The distal portion 172 of the second end cap 160 is also disk-like inshape, having a diameter D7 that is smaller than the diameter D6 of theproximate portion 162. The distal portion 172 of the second end cap 160contains a top surface 174 and an outer surface 176. In addition, thedistal portion 172 of the second end cap 160 has a length L3, where thelength L3 of the distal portion 172 is smaller than the length L2 of thehollow center 150 of the central member 140. In fact, as is shownhereinafter with regard to FIGS. 2-4, the length L2 of the hollow center150 is larger than the combination of the length L3 of the distalportion 172 of the second end cap 160 combined with the length L1 of thecylindrical gap 128 of the first end cap 110.

It should be noted that, while the outer surface 176 of the distalportion 172 is shown as being flat, one having ordinary skills in theart would appreciate that the outer surface 176 need not be flat.Progression from the proximate portion 162 of the second end cap 160 tothe distal portion 172 of the second end cap 160 is defined by a stepwhere a top portion of the step is defined by the top surface 166 of theproximate portion 162, a middle portion of the step is defined by theinternal surface 168 of the proximate portion 162, and a bottom portionof the step is defined by the top surface 174 of the distal portion 172.

Within the distal portion 172 of the second end cap 160, the outersurface 176 joins the top surface 174. It should be noted that whileFIG. 4 shows the cross-section of the outer surface 176 as being squaredto the top surface 174, the outer surface 176 may instead be rounded orof a different shape. Referring to FIG. 4, the distal portion 172 of thesecond end cap 160 is shown to be an extension of the proximate portion162 of the second end cap 160. It should be noted that while FIG. 4illustrates the outer surface 176 as running parallel to the flat endsurface 164, the outer surface 176 may instead be concave, conical, orhemispherical.

It should be noted that dimensions of the second end cap 160 arepreferably similar to the dimensions of the first end cap 110.Therefore, the diameter D4 of the central member 140 hollow center 150is also just slightly larger that the diameter D7 of the second end cap160, thereby allowing the distal portion 172 of the second end cap 160to fit within the hollow center 150 of the central member 140. Inaddition, the diameter D6 (i.e., the diameter of the proximate portion162 of the second end cap 160) is preferably slightly larger thatdiameter D5 (i.e., the diameter of the central member 140). Further,when the tilt sensor 100 is assembled, the distal surface 148 of thecentral member 140 rests against the internal surface 168 of the secondend cap 160.

Referring to FIG. 1, when the tilt sensor 100 is assembled, the pair ofconductive spheres 190 (also referred to as conductive weights),including a first conductive sphere 192 and a second conductive sphere194, fit within the central member 140, within a portion of thecylindrical gap 128 of the first distal portion 122 of the first end cap110, and a space provided between the outer surface 130 of the first endcap 110 and the outer surface 176 of the second end cap 110.

Specifically, the inner surface 132, bottom surface 126, and outersurface 130 of the first end cap 110, the bottom surface 146 of thecentral member 140, and the outer surface 176 of the second end cap 160form a central cavity 200 of the tilt sensor 100, where the pair ofconductive spheres 190 are confined.

Further illustration of location of the conductive spheres 190 isprovided and illustrated with regard to FIG. 6A and FIG. 6B, and FIGS.7A-7E. It should be noted that, while the figures in the presentdisclosure illustrate both of the conductive spheres 190 as beingsubstantially symmetrical, alternatively, one sphere may be larger thanthe other sphere. Specifically, as long as the conductive relationshipsdescribed herein are maintained, the conductive relationships may bemaintained by both spheres being larger, one sphere being larger thanthe other, both spheres being smaller, or one sphere being smaller. Itshould be noted that the conductive spheres 190 may instead be in theshape of ovals, cylinders, or any other shape that permits motion withinthe central cavity 200 in a manner similar to that described herein.

Due to minimal components, assembly of the sensor 100 is quitesimplistic. Specifically, there are four components, namely, the firstend cap 110, the central member 140, the conductive spheres 190, and thesecond end cap 160. FIG. 5 is a flowchart illustrating a method ofassembling the tilt sensor 100 of FIG. 1. It should be noted that anyprocess descriptions or blocks in flowcharts should be understood asrepresenting modules, segments, portions of code, or steps that includeone or more instructions for implementing specific logical functions inthe process, and alternate implementations are included within the scopeof the present invention in which functions may be executed out of orderfrom that shown or discussed, including substantially concurrently or inreverse order, depending on the functionality involved, as would beunderstood by those reasonably skilled in the art of the presentinvention.

As is shown by block 202, the distal portion 122 of the first end cap110 is fitted within the hollow center 150 of the central member 140 sothat the proximate surface 144 of the central member 140 is adjacent toor touching the internal surface 118 of the first end cap 110. Theconductive spheres 190 are then positioned within the hollow center 150of the central member 140 and within a portion of the cylindrical gap128 (block 204). The distal portion 172 of the second end cap 160 isthen fitted within the hollow center 150 of the central member 140, sothat the distal surface 148 of the central member 140 is adjacent to ortouching the internal surface 168 of the second end cap 160 (block 206).

When assembled, the inner surface 132, bottom surface 126, and outersurface 130 of the first end cap 110, the bottom surface 146 of thecentral member 140, and the outer surface 176 of the second end cap 160form the central cavity 200 of the tilt sensor 100 where the pair ofconductive spheres 190 are confined.

In accordance with an alternative embodiment of the invention, the tiltsensor 100 may be assembled in an inert gas, thereby creating an inertenvironment within the central cavity 200, thereby reducing thelikelihood that the conductive spheres 190 will oxidize. As is known bythose having ordinary skill in the art, oxidizing of the conductivespheres 190 would lead to a decrease in the conductive properties of theconductive spheres 190. In addition, in accordance with anotheralternative embodiment of the invention, the first end cap 110, thecentral member 140, and the second end cap 160 may be joined by a seal,thereby preventing any contaminant from entering the central cavity 200.

The sensor 100 has the capability of being in a closed state (ON) or anopen state (OFF), depending on location of the conductive spheres 190within the central cavity 200 of the tilt sensor 100. FIG. 6A and FIG.6B are cross-sectional views of the tilt sensor 100 of FIG. 1 in aclosed state (ON), in accordance with the first exemplary embodiment ofthe invention. In order for the tilt sensor 100 to be maintained in aclosed state (ON), an electrical charge introduced to the first end cap110 is required to traverse at least one conductive sphere 192, 194 andbe received by the second end cap 160. For this reason, it should benoted that in accordance with an alternative embodiment of theinvention, the tilt sensor 100 may also only contain a single conductivesphere 190 (FIG. 6D).

Referring to FIGS. 6A and 6B, the tilt sensor 100 is in a closed state(ON) because the second conductive sphere 194 is touching the bottomsurface 126 of the first end cap 110 and the second conductive sphere194 is touching the outer surface 176 of the second end cap 160, therebyproviding a conductive path from the first end cap 110, through thesecond conductive sphere 194, to the second end cap 160.

FIG. 6C is a cross-sectional side view of the tilt sensor 100 having thecentral member 610 of FIG. 3B. As shown, the tilt sensor 100 of FIG. 6Cis in a closed state (ON).

It should be noted that in accordance with the first exemplaryembodiment of the invention, a distance between the first end cap 110and the second end cap 160 (also referred to herein as a “gap”), whenthe tilt sensor 100 is assembled, is not so large as to allow the secondconductive sphere 194 to fall therein. As a result of the gap not beingtoo large, the tilt sensor 100 is very sensitive and allows for changingstates from a closed state (ON) to an open state (OFF), or from an openstate (OFF) to a closed state (ON), with slight tilting of the tiltsensor 100.

In accordance with a second exemplary embodiment of the invention, asshown by FIG. 6E the distance between the first end cap 110 and thesecond end cap 160 is large enough to allow the second conductive sphere194 to rest within a gap created by the distance. It should be notedthat, in accordance with the second exemplary embodiment of theinvention, the gap is not large enough that the second conductive sphere194 would be difficult to dislodge from the gap. Instead, the size ofthe gap dictates the angle of tilt required to allow the secondconductive sphere 194 to move out of the gap, thereby making changingstates of the tilt sensor 100 from a closed state (ON) to an open state(OFF) more difficult in the tilt sensor 100 of the second exemplaryembodiment than in the tilt sensor 100 of the first exemplary embodimentof the invention.

FIG. 7A-FIG. 7D are cross-sectional views of the sensor 100 of FIG. 1 inan open state (OFF), in accordance with the first exemplary embodimentof the invention. In order for the tilt sensor 100 to be maintained inan open state (OFF), an electrical charge introduced to the first endcap 110 cannot traverse the second conductive sphere 194 and be receivedby the second end cap 160. Referring to FIGS. 7A-7D, each of the tiltsensors 100 displayed are in an open state (OFF) because the secondconductive sphere 194 is not in contact with the second end cap 160. Ofcourse, other arrangements of the first and second conductive spheres192, 194 within the central cavity 200 of the tilt sensor 100 may beprovided as long as no conductive path is provided from the first endcap 110 to the second conductive sphere 194, to the second end cap 160.

FIG. 8 is a cross-sectional side view of the present tilt sensor 300, inaccordance with a third exemplary embodiment of the invention. The tiltsensor 300 of the third exemplary embodiment of the invention does notcontain a flange on the first end cap 110 or a flange on the second endcap 160.

FIG. 9 is a cross-sectional side view of the present tilt sensor 400, inaccordance with a fourth exemplary embodiment of the invention. The tiltsensor 400 of the fourth exemplary embodiment of the invention does notcontain a flange on the first end cap 110 or a flange on the second endcap 160. In addition, the central member 140 extends over the proximateportion 112 and a distal portion 122 of the first end cap 110, and overthe proximate portion 162 and a distal portion 172 of the second end cap160.

FIG. 10 is a cross-sectional side view of the present tilt sensor 500,in accordance with a fifth exemplary embodiment of the invention. Thetilt sensor 500 of the fifth exemplary embodiment of the inventioncontains a first nub 502 located on the flat end surface 114 of thefirst end cap 110 and a second nub 504 located on a flat end surface 164of the second end cap 160. The nubs 502, 504 provide a conductivemechanism for allowing the tilt sensor 500 to connect to a printedcircuit board (PCB) landing pad, where the PCB landing pad has anopening cut into it allowing the tilt sensor 500 to recess into theopening. Specifically, dimensions of the tilt sensor 500 may be selectedso as to allow the tilt sensor 500 to fit within a landing pad of a PCB.Within the landing pad there may be a first terminal and a secondterminal. By using the nubs 502, 504, fitting the tilt sensor 500 intolanding pad may press the first nub 502 against the first terminal andthe second nub 504 against the second terminal. Those having ordinaryskill in the art would understand the basic structure of a PCB landingpad, therefore, further explanation of the landing pad is not providedherein.

It should be noted that the tilt sensors described herein may have thesame basic shape, thereby contributing to ease of preparing a printedcircuit board (PCB) for receiving the tilt sensor. Specifically, a holemay be cut in a PCB the size of the tilt sensor (i.e., the size of thefirst and second end caps 110, 160 and the central member 140) so thatthe tilt sensor can drop into the hole, where the tilt sensor isprevented from falling through the hole when caught by the nubs 502, 504that land on connection pads. In the exemplary embodiments of theinvention where there are no nubs 502, 504, the end caps may be directlymounted to the PCB.

In accordance with another alternative embodiment of the invention, thetwo conductive spheres may be replaced by more than two conductivespheres, or other shapes that are easily inclined to roll when thesensor 100 is moved.

FIG. 11A and FIG. 11B are cross-sectional side views of a tilt sensor600, in accordance with a sixth exemplary embodiment of the invention.As is show by FIGS. 11A and 11B, the first and second end caps 610, 660have a top lip portion that overlaps a portion of the central member140. The embodiment of the central member 140 illustrated by FIG. 11Aand FIG. 11B is the central member 140 of FIG. 3A.

The first end cap 610 contains a first top lip portion 620 that overlapsthe top surface 142 of the central member 140. The first top lip portion620 of the first end cap 610 is shown to overlap the top surface 142 ofthe central member 140 more in the embodiment of FIG. 11B than in theembodiment of FIG. 11A. The second end cap 630 contains a second top lipportion 640 that overlaps the top surface 142 of the central member 140.The first top lip portion 620 and the second top lip portion 640 form acavity in which the central member 140 fits when assembling the tiltsensor 600.

It should be emphasized that the above-described embodiments of thepresent invention are merely possible examples of implementations,merely set forth for a clear understanding of the principles of theinvention. Many variations and modifications may be made to theabove-described embodiments of the invention without departingsubstantially from the spirit and principles of the invention. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure and the present invention and protected bythe following claims.

1. A tilt sensor, comprising: a first electrically conductive element,having a first diameter on a proximate portion of the first electricallyconductive element and a second diameter on a distal portion of thefirst electrically conductive element, where the second diameter of thefirst electrically conductive element is smaller than the first diameterof the first electrically conductive element; a second electricallyconductive element, having a first diameter on a proximate portion ofthe second electrically conductive element and a second diameter on adistal portion of the second electrically conductive element, where thesecond diameter of the second electrically conductive element is smallerthan the first diameter of the second electrically conductive element,wherein the distal portion of the first electrically conductive elementfaces the distal portion of the second electrically conductive element;an electrically insulative element connected to the first electricallyconductive element and the second electrically conductive element; and aplurality of electrically conductive weights located within a cavity ofthe tilt sensor, wherein the cavity is defined by at least one surfaceof the first electrically conductive element, at least one surface ofthe electrically insulative element, and at least one surface of thesecond electrically conductive element, wherein the distal portion ofthe first electrically conductive element is separated from the distalportion of the second electrically conductive element by a gap, andwherein none of the electrically conductive weights is capable offalling into the gap.
 2. The tilt sensor of claim 1, wherein the tiltsensor is in a closed state (ON) if a conductive path exists from thefirst electrically conductive element, through at least one of theplurality of electrically conductive weights, through the secondelectrically conductive element, and wherein the tilt sensor is in anopen state (OFF) if there is no conductive path from the firstelectrically conductive element, through at least one of the pluralityof electrically conductive weights, through the second electricallyconductive element.
 3. The tilt sensor of claim 1, wherein the firstelectrically conductive element is sealed to the electrically insulativeelement and the second electrically conductive element is sealed to theelectrically insulative element.
 4. The tilt sensor of claim 1, whereinthe tilt sensor is further defined by: the first electrically conductiveelement further comprises a flat end surface located on a side oppositethe distal portion of the first electrically conductive element; andwherein the second electrically conductive element further comprises aflat end surface located on a side opposite the distal portion of thesecond electrically conductive element.
 5. The tilt sensor of claim 4,wherein the flat end surface of the first electrically conductiveelement contains a first nub for providing electrical contact of thefirst electrically conductive element to a first terminal, and whereinthe flat end surface of the second electrically conductive elementcontains a second nub for providing electrical contact of the secondelectrically conductive element to a second terminal.
 6. The tilt sensorof claim 4, wherein the cavity is filled with an inert gas.
 7. The tiltsensor of claim 1, wherein the diameter of the distal portion of thefirst electrically conductive element and the diameter of the distalportion of the second electrically conductive element are smaller than adiameter of the electrically insulative element.
 8. The tilt sensor ofclaim 1, wherein the distal portion of the first electrically conductiveelement is longer than the distal portion of the second electricallyconductive element.
 9. The tilt sensor of claim 1: wherein the distalportion of the first electrically conductive element fits within aproximate end of the electrically insulative element, and wherein thedistal portion of the second electrically conductive element fits withina distal end of the electrically insulative element.
 10. The tilt sensorof claim 9, wherein the proximate portion of the first electricallyconductive element and the proximate portion of the second electricallyconductive element are located external to the electrically insulativeelement.
 11. The tilt sensor of claim 9, further defined by: theproximate portion of the first electrically conductive element furthercomprising a top surface and an end surface; and the proximate portionof the second electrically conductive element further comprising a topsurface and an end surface, wherein the top surface of the firstelectrically conductive element and the top surface of the secondelectrically conductive element are located internal to the electricallyinsulative element.
 12. The tilt sensor of claim 11, wherein the endsurface of the first electrically conductive element and the end surfaceof the second electrically conductive element are located external tothe electrically insulative element.
 13. The tilt sensor of claim 9,wherein the distal portion of the first electrically conductive elementfurther comprises: a first top surface; a first outer surface; and afirst bottom surface, wherein the first top surface, the first outersurface, and the first bottom surface form a first cylindrical lip ofthe first electrically conductive element, and wherein the distalportion of the second electrically conductive element further comprises:a second top surface; and a second outer surface.
 14. The tilt sensor ofclaim 1, wherein the electrically insulative element is tube-like inshape.
 15. The tilt sensor of claim 1, wherein the electricallyinsulative element is square-like in shape.
 16. The tilt sensor of claim1, further defined by: the distal portion of the first electricallyconductive element further comprises a cylindrical gap; the distalportion of the second electrically conductive element further comprisesan outer surface; the first electrically conductive element furthercomprising a first top lip portion; and the second electricallyconductive element further comprising a second top lip portion, whereinthe first top lip portion and the second top lip portion fit over aportion of a top surface of the electrically insulative element.
 17. Amethod of constructing a tilt sensor having a first electricallyconductive element having a first diameter on a proximate portion of thefirst electrically conductive element and a second diameter on a distalportion of the first electrically conductive element, where the seconddiameter is smaller than the first diameter, a second electricallyconductive element having a first diameter on a proximate portion of thesecond electrically conductive element and a second diameter on a distalportion of the second electrically conductive element, where the seconddiameter is smaller than the first diameter, an electrically insulativeelement, and a plurality of electrically conductive weights, wherein thedistal portion of the first electrically conductive element is separatedfrom the distal portion of the second electrically conductive element bya gap, and wherein none of the electrically conductive weights iscapable of falling into the gap, the method comprising the steps of:fitting the distal portion of the first electrically conductive elementwithin a hollow center of the electrically insulative member;positioning the plurality of electrically conductive weights within thehollow center of the electrically insulative member; and fitting thedistal portion of the second electrically conductive element within thehollow center of the electrically insulative member.
 18. The method ofclaim 17, further comprising the step of fabricating a first nub on aproximate portion of the first conductive element and a second nub on aproximate portion of the second conductive element.
 19. The method ofclaim 17, wherein the method of constructing the tilt sensor isperformed in an inert gas.
 20. The method of claim 17, furthercomprising the steps of: sealing the first electrically conductiveelement to the electrically insulative element; and sealing the secondelectrically conductive element to the electrically insulative element.21. A tilt sensor, comprising: a first electrically conductive element,having a proximate portion and a distal portion, where the distalportion of the first electrically conductive element contains a topsurface, a bottom surface, and an outer surface, wherein the bottomsurface of the distal portion defines an exterior portion of a gap ofthe distal portion, and wherein the bottom surface and the outer surfaceof the distal portion join at an edge; a second electrically conductiveelement, having a proximate portion and a distal portion; anelectrically insulative element connected to the first electricallyconductive element and the second electrically conductive element; andonly one electrically conductive weight located within a cavity of thetilt sensor, wherein the cavity is defined by at least one surface ofthe first electrically conductive element, at least one surface of theelectrically insulative element, and at least one surface of the secondelectrically conductive element, and wherein a distance between theouter surface of the first electrically conductive element distalportion and the distal portion of the second electrically conductiveelement does not allow the electrically conductive weight to fall withinthe distance.
 22. The tilt sensor of claim 21, wherein the tilt sensoris in a closed state (ON) if a conductive path exists from the firstelectrically conductive element, through the electrically conductiveweight, through the second electrically conductive element, and whereinthe tilt sensor is in an open state (OFF) if there is no conductive pathfrom the first electrically conductive element, to the electricallyconductive weight, to the second electrically conductive element. 23.The tilt sensor of claim 21, wherein a diameter of the distal portion ofthe first electrically conductive element and a diameter of the distalportion of the second electrically conductive element are smaller than adiameter of the electrically insulative element.
 24. The tilt sensor ofclaim 21, wherein: the first electrically conductive element has a firstdiameter on the proximate portion of the first electrically conductiveelement and a second diameter on the distal portion of the firstelectrically conductive element, where the second diameter is smallerthan the first diameter; and the second electrically conductive elementhas a first diameter on the proximate portion of the second electricallyconductive element and a second diameter on the distal portion of thesecond electrically conductive element, where the second diameter issmaller than the first diameter, wherein the distal portion of the firstelectrically conductive element fits within a proximate end of theelectrically insulative element, and wherein the distal portion of thesecond electrically conductive element fits within a distal end of theelectrically insulative element.
 25. The tilt sensor of claim 24,further defined by: the proximate portion of the first electricallyconductive element further comprising a top surface and an end surface;and the proximate portion of the second electrically conductive elementfurther comprising a top surface and an end surface, wherein the topsurface of the first electrically conductive element and the top surfaceof the second electrically conductive element are located internal tothe electrically insulative element.
 26. The tilt sensor of claim 24,wherein the distal portion of the second electrically conductive elementfurther comprises: a second top surface; and a second outer surface. 27.The tilt sensor of claim 21, further defined by: the first electricallyconductive portion further comprising a first top lip portion; and thesecond electrically conductive portion further comprising a second toplip portion, wherein the first top lip portion and the second top lipportion fit over a portion of a top surface of the electricallyinsulative element.
 28. The tilt sensor of claim 27, wherein: the atleast one surface of the first electrically conductive element is asurface that defines the gap; the at least one surface of theelectrically insulative element is a bottom surface of the electricallyinsulative element; and the at least one surface of the secondelectrically conductive element is the outer surface of the seconddistal portion.